Various types of apparatus have been developed for opening and closing large doors, including upward-acting garage doors and so-called rollup doors. Motor-driven operator units for industrial doors, including upward-acting doors of various types, have been developed which include mechanism for manually or automatically allowing the door to close under certain operating condition.
Various improvements have been sought in door operator units which are motor-driven but which also may be operated when motor power is unavailable or when the door is required to be closed under its own weight or another source of power. However, reliable and versatile operation of door operator units, compact and lightweight construction of such units and the ability to interchange the position of components of the operator unit, depending on the door configuration or application, continue to be problems facing artworkers. It is to these ends that the present invention has been developed.
The present invention provides an improved door operator unit, particularly of a type for opening and closing upward-acting, sectional and so-called rollup doors of various configurations.
In accordance with one aspect of the present invention, a motor driven door operator unit is provided which includes an improved power transmission mechanism between a drive motor and an operator unit output shaft. In particular, the power transmission mechanism includes a differential planetary gear drive drivenly connected to a drive motor and a remotely controlled brake operably connected to the motor output shaft for controlling rotation of the operator unit output shaft under certain operating conditions.
In accordance with another aspect of the invention, a door operator unit is provided which includes a differential planetary gear drive mechanism having a first ring gear which is normally held stationary to provide suitable speed reduction and torque amplification between a motor output shaft and the operator unit output shaft. A first ring gear member is held stationary during normal operation of the unit under motor power but may be released to rotate under certain operating conditions, such as when it is desirable to manually open or close a door connected to the operator unit. In this regard also, the releasable ring gear may be drivenly connected to a manual or separately driven shaft for driving the operator unit output shaft to rotate in either direction. Still further, the operator unit includes a release mechanism for holding the first ring gear stationary under selected operating conditions and for allowing the first ring gear to rotate, thus allowing rotation of the operator unit output shaft under other operating conditions.
The present invention also provides a door operator unit which includes a differential planetary gear drive mechanism having a first ring gear which may be held stationary or allowed to rotate and a second ring gear which also comprises an output gear of the operator unit. The second ring gear is operably connected to the operator unit output shaft through an adjustable torque limiting clutch whereby the output torque exerted on a door or door drive mechanism connected to the operator unit may be limited, and may be selectively adjusted.
The present invention provides an improved door operator unit drive mechanism which is adapted to include a gear for driving a sensor, such as a door position limit switch, which gear is positively keyed to rotate with the operator unit output shaft to prevent loss of timing between the position of the door and the limit switch.
Still further, an improved operator unit is provided which is adapted to reverse the positions of a manual operator drive shaft and a release mechanism. The operator unit includes an improved arrangement of a manually operated or auxiliary power operated drive shaft, associated drive mechanism and a speed limiting governor.
The present invention includes all of the above-mentioned features in a compact and reliable door operator unit, which will be further appreciated by those skilled in the art upon reading the detailed description which follows in conjunction with the drawing.